1. Field of the Invention
The present invention relates to a developing device and a process cartridge for use in an image forming apparatus such as a copying apparatus or a page printer for forming an image with an electrophotographic image forming process or an electrostatic recording process, and such electrophotographic image forming apparatus.
2. Related Background Art
The image forming apparatus employing an electrophotographic image forming method is provided with developing means for developing a latent image, formed on a photosensitive drum, with toner. Such developing means can be a developing device provided with a developing member for supplying the photosensitive drum with developer, and a developing container for storing the developer, and, such developing container is provided therein with an agitating rod for agitating and transporting the developer. The agitating rod is, for example, crank-shaped and is supported at an end thereof by a driving gear which is rotatably supported on a lateral wall, at the driving side, of the developing container, and also supported at the other end by a lateral wall, at the non-driving side, of the developing container.
Such developing device may be of a type which is incorporated in the main body of the image forming apparatus and in which the developer is replenished into the developing container when the developer contained therein decreases, or a process cartridge type in which the electrophotographic photosensitive member and process means acting on such photosensitive member and including at least the developing means are integrally formed as a cartridge detachable from the main body of the image forming apparatus. Such process cartridge system can significantly improve operability since the maintenance of the apparatus can be executed by the user himself. For this reason, such process cartridge system is widely employed in image forming apparatus.
In the supporting portion of the aforementioned agitating rod, the inner wall of the bearing hole and the agitating rod are in mutual friction, and, if the toner enters such frictional portion, there may be developed coarse toner particles of 20 to 200 .mu.m by mechanical stamping or eventually thermal fusion of the toner. Such coarse toner particles are mixed with the ordinary toner particles and migrate in the toner container, and may be clogged between the developing limiting member and the developing sleeve.